New Rotor and Pads - Rotor Glazed Why?

[Sawblade]

I put a new EBC rear rotor, EBC carbon pads and changed the brake fluid using Dot 4 Honda brake fluid on my 02 CR 250 last week. I went riding yesterday and keep losing the back brake. I used a vacuum pump for the first time as I have never had much luck bleeding brakes the old fashion way. I pulled fluid until it was clear and the petal felt firm, but since I can pump the pedal once or twice and the brake comes back I probably have an air bubble to work out. So back to bleeding the brake again.

After putting in a few laps I head back to the pits. After putting the bike on the stand I notice the back rotor on both sides had a dark residue or glazed on it. When I put the rotor on I wiped it clean with brake cleaner to remove any oil. The rotor didn't feel like it had anything on it when I took it out of the package.

So, my question are:

1 - Brake fluid on the rotor from bleeding them, which I don't feel is the source of the problem.

2 - The pipe/silencer junction was leaking because I didn't get the collar in place as it should have been. Again, I feel this is not the source of the problem either.

3 - I didn't get the rotor wiped clean and the oil or what ever was put on the rotor at the factory glazed the rotor.

This afternoon I took the back wheel off. I used a Scott brite pat to removed the glaze, then flipped the rotor to do the other side.
See the link for a picture of the glazed rotor.

http://www.imagestation.com/mypictu.../f6f4512f.jpg&caption=Rotor 004&id=4143206703

I'm stumped, can someone point me in the right direction?

 

[Sawblade]

Could the pads have had something on them to cause the glazing? Do I need to replace the new pads? I may try to sand them a little to remove any glazing on them.

 

[marcusgunby]

Some pads will glaze no matter what-dps i tend to find to this, i use the softer ebc pads(red on the material at the back) these are really good but i suspect will wear fast in mud.

 

[Sawblade]

Some pads will glaze no matter what-dps i tend to find to this, i use the softer ebc pads(red on the material at the back) these are really good but i suspect will wear fast in mud.

Marcus,

This is the first time I have had new pads glaze. But then , this is the first time I've replaced a rotor on a bike also. As for the EBC pads I bought the carbon ones that are red as EBC's information said they ran cooler but wear faster.

I finished removing the glaze last night from the rotor and sanded the glaze from the pads as will. Do you think the rotor will glaze again?

 

[marcusgunby]

Make sure its not dragging -can be due to seized slider pins, does the pads move out easily if you pry them apart?? ie stuck pistons??retaining pin not notched?

 

[Jeff Howe]

It's because the zinc coating on the rotor contaminates the pads. Clean the rotor with a scotchbrite pad and brake cleaner and then surface the pads on some 220 grit and you'll be fine. You should always clean the zinc off the new rotor before you use it. Like anybody else I learned this the hard way. I always wire wheel (and clean) new discs now that are zinc coated before I use them.

 

[Sawblade]

Marcus,
Yes, the slider pin is fine and the piston moves freely.

Shocknut,
Yes, I learned this the hard way also. :bang: I did the scotchbrite pad and sand paper on the pads last night. I will clean the rotor tomorrow after buying more brake cleaner.

Thanks to both of you for helping to clear the mystery. :cool: